Michael Phelps

Corbis

AGE: 23
OCCUPATION: Olympian
PREVIOUS APPEARANCES ON THE TIME 100: 0

PRO: When it came to sheer spectacle, nothing at last year's Beijing Olympics  not the gazillion drummers, not the lip-synching tot  could top Phelps' eight-medal run. And as far as advertisers are concerned, Phelps practically walks on water, earning millions of dollars in endorsement deals.

CON: He needs to learn to avoid undergrads with misshapen pipes and digital cameras.